Notes on food habits of swamp rabbits (Sylvilagus aquaticus) in the Atchafalaya Basin, Louisiana.ABSTRACT Plants cut by wild swamp rabbits (Sylvilagus aquaticus) were noted in the Atchafalaya Basin
The Atchafalaya Basin, or Atchafalaya Swamp , Louisiana during summer 1994 and winter 1995. Food preferences were apparent. Woody vegetation was frequently used during both summer and winter, but more so during winter. INTRODUCTION AND STUDY AREA Plants cut by wild swamp rabbits (Sylvilagus aquaticus) were noted as part of a study aimed to assess swamp rabbit habitat in the Atchafalaya Basin, Louisiana after Hurricane Andrew This article is about the 1992 hurricane; there was also a Tropical Storm Andrew during the 1986 Atlantic hurricane season. Hurricane Andrew is the second-most-destructive hurricane in U.S. history, and the last of three Category 5 hurricanes that made U.S. struck in August 1992 (Helm 1995). Food habits of swamp rabbits vary regionally and have been studied in Louisiana on captive rabbits fed selected plants (Richardson 1963; Sullivan 1966), free ranging rabbits using food plots (Croft 1961), and penned rabbits using natural habitat modified by timber thinning (Garner 1969). The study area occurs at elevations less than 3.0 m msl (U.S.D.I. Geol. Surv. 1953a and 1953b) within a very gentle ridge-swale complex in a swamp environment. The study area was characterized by varying degrees of hurricane damage (designated as low, moderate, and high), two forest types [bottomland hardwood ridges and slightly lower baldcypress (Taxodium distichum)-tupelogum (Nyssa aquatica) swales], and two tree sizes (pulpwood pulp·wood n. Soft wood, such as spruce, aspen, or pine, used in making paper. pulpwood Noun pine, spruce, or any other soft wood used to make paper Noun 1. and sawtimber) (see Helm 1995; Salyer 1995) and located south of Interstate 10 between the Atchafalaya and Mississippi Rivers in Iberville Parish, Louisiana Iberville Parish (French: Paroisse d'Iberville) is a parish located south of Baton Rouge in the U.S. state of Louisiana. Its seat is Plaquemine. In 2000, the population of the parish was 33,320. . Thirty-three study plots were located approximately 10 km south of Ramah in sections 59 and 61 (T8S-R S-R Stimulus-Response (Pavlovian psychology) S-R Set-Reset 10E) on property used by the Red Diamond Hunting Club. Fifteen plots were located approximately 10 km west of Plaquemine and about 15 km east of the above-mentioned plots in section 9 (T9S-R11E) on property used by the Shell Road Hunting Club. Common trees on ridges included boxelder (Acer negundo), red maple red maple see acerrubrum. (Acer rubrum), sugarberry sug·ar·ber·ry n. See hackberry. Noun 1. sugarberry - deciduous shade tree with small black berries; southern United States; yields soft yellowish wood Celtis laevigata (Celtis laevigata Noun 1. Celtis laevigata - deciduous shade tree with small black berries; southern United States; yields soft yellowish wood sugarberry Celtis, genus Celtis - large genus of trees and shrubs with berrylike fruit ), green ash (Fraxinus pennsylvanica), sweetgum (Liquidambar styraciflua), and American elm (Ulmus americana). Baldcypress and tupelogum were dominant in swales. Understory un·der·sto·ry n. An underlying layer of vegetation, especially the plants that grow beneath a forest's canopy. vegetation was diverse and frequencies of all recorded understory plants are appended in Helm (1995). Small elevation differences greatly impact durations of flooding within the study area. Swales generally support at least some standing water most of the year while ridges typically support standing water only after heavy rainfall. METHODS Plots were established during summer 1993. Four subplots were randomly located within each of 48, 0.1 ha plots and subplots were divided into 1 [m.sup.2] quadrats, resulting in 768 quadrats. Equal numbers of plots were established in each combination of hurricane damage, forest type, and tree size. Presence of all understory plant taxa taxa: see taxon. and the number and taxa of stems cut by swamp rabbits, as indicated by a smooth 45[degrees] angle cut (Garner 1969), were recorded in each quadrat quad·rat n. 1. Printing A piece of type metal lower than the raised typeface, used for filling spaces and blank lines. Also called quad2. 2. during August 1994 and January 1995. Timber harvesting on 8 of the 0.1 ha plots resulted in 640 quadrats sampled during January 1995. Understory vegetation was defined as plants occurring to a maximum height of 1 m. Plants were required to be rooted in a quadrat to be considered present. Eastern cottontails (Sylvilagus floridanus Noun 1. Sylvilagus floridanus - widely distributed in United States except northwest and far west regions eastern cottontail cottontail, cottontail rabbit, wood rabbit - common small rabbit of North America having greyish or brownish fur and a tail with a ) were observed on the open grounds around the Red Diamond Hunting Club lodge but never on the study plots, while swamp rabbits were observed on the study plots. Discussions with hunters substantiated these observations. The eastern cottontail is typically found in fairly open country, pastures, and grassy areas and is replaced by the swamp rabbit in swamps and marshes (Lowery low·er·y also lour·y adj. Overcast; threatening. 1974). All observed smooth 45[degrees] angle cuts were considered to be from swamp rabbits. RESULTS AND DISCUSSION Woody and herbaceous her·ba·ceous adj. 1. Relating to or characteristic of an herb as distinguished from a woody plant. 2. Green and leaflike in appearance or texture. vegetation cut by swamp rabbits within quadrats was noted during summer 1994 (Table 1) and winter 1995 (Table 2). Most cuttings were within 20 cm of the ground and none were higher than 45 cm. Woody plants comprised 49.1% of all identified swamp rabbit cuttings during summer 1994 and 85.4% during winter 1995. Cuttings on stems with diameters to 0.6 cm at the cut were observed. Woody vegetation has previously been identified as an important constituent of the swamp rabbit diet only in northern parts of the rabbit's range including Missouri (Toll et al. 1960), Oklahoma (Smith 1940), Indiana (Terrel 1972), and Tennessee (Calhoun 1941). No other studies on food habits of swamp rabbits have been conducted in the Atchafalaya Basin but Garner (1969) investigated swamp rabbit food habits in a similar bottomland hardwood forest subject to periodic inundation INUNDATION. The overflow of waters by coming out of their bed. 2. Inundations may arise from three causes; from public necessity, as in defence of a place it may be necessary to dam the current of a stream, which will cause an inundation to the upper lands; in LaSalle Parish, Louisiana, approximately 120 km north of the study area. Although woody plants were common in the understory, no woody plants were observed to be cut by swamp rabbits during summer 1968 and only sparse use of woody plants (13.3% of total) was noted during winter 1969. Understory cover was related to hurricane damage (summer 1994), forest type (summer 1993, summer 1994, and winter 1995), and combinations of forest type and tree size (summer 1993, summer 1994, and winter 1995) and is discussed in Helm (1995) and Helm and Chabreck (2004). Number of cuttings by swamp rabbits, however, was not related to understory cover but was greater on ridges than in swales during winter 1995 (see Helm 1995), likely because of drier conditions on ridges. Savannah Savannah, city, United States Savannah, city (1990 pop. 137,560), seat of Chatham co., SE Ga., a port of entry on the Savannah River near its mouth; inc. 1789. panicgrass (Phanopyrum gymnocarpon) during summer and greenbrier greenbrier: see smilax. (Smilax smilax, common name for a florists' plant of two separate genera (Asparagus and Smilax), both of the family Liliaceae (lily family, although some botanists recognize smilax as a separate family, the Similacaceae). spp.) during summer and winter appear to be preferred foods, given the relatively large number of cuttings on these plants and their low frequencies of occurrence. Dewberry dewberry, name for several species of the genus Rubus of the family Rosaceae (rose family). See bramble. dewberry Any blackberry (genus Rubus) that is so lacking in woody fibre in the stems that it trails along the ground. (Rubus spp.) was abundant and commonly used in summer and winter. While woody understory plants were common in Garner's LaSalle Parish study, greenbrier and dewberry were not; perhaps summer use of woody plants in Louisiana swamps occurs when specific favored plants are present. Palatable herbaceous forage may be limited during winter in the Atchafalaya Basin as indicated by a marked decrease in use from summer to winter. A less dramatic shift to woody plant use from summer to winter occurred in the LaSalle Parish study. Food availability has generally not been considered a limiting factor A factor or condition that, either temporarily or permanently, impedes mission accomplishment. Illustrative examples are transportation network deficiencies, lack of in-place facilities, malpositioned forces or materiel, extreme climatic conditions, distance, transit or overflight rights, for swamp rabbit populations but Sims (1956) indicated that herbaceous forage may be scarce in Louisiana during winter. A total of 46 plant taxa during summer 1994 and 54 plant taxa during winter 1995 in the Atchafalaya Basin showed no evidence of cutting by swamp rabbits. ACKNOWLEDGMENTS This study was funded by the Southern Science Center of the National Biological Survey, the Louisiana Cooperative Fish and Wildlife Research Unit, and the Louisiana State University Louisiana State University and Agricultural and Mechanical College, generally known as Louisiana State University or LSU, is a public, coeducational university located in Baton Rouge, Louisiana and the main campus of the Louisiana State University System. Agricultural Center and was conducted on property owned by the Louisiana Division of Dow Chemical, U.S.A., Inc. and Wilbert's Sons Limited Partnership, Inc. LITERATURE CITED Calhoun, J.B. 1941. Distribution and food habits of mammals in the vicinity of the Reelfoot Lake Reelfoot Lake, 20 mi (32 km) long, NW Tenn., near the Mississippi River; designated a national natural landmark by the National Park Service. It was formed when a depression created by earthquakes in the winter of 1811–12 was filled with Mississippi River water. Biological Station. J. Tennessee Acad. Sci. XVI(2):207-225. Croft, R.L. 1961. The value of food plots to cottontail cottontail a wild rabbit, Sylvilagus spp. and swamp rabbits in Louisiana. M.S. Thesis, Louisiana State Univ., Baton Rouge, Louisiana For the Canadian restaurant, see . Baton Rouge (from the French bâton rouge), pronounced /ˈbætn ˈɹuːʒ/ in English, and . 61 pp. Garner, G.W. 1969. Short-term succession of vegetation following habitat manipulation of bottomland hardwoods for swamp rabbits in Louisiana. M.S. Thesis, Louisiana State Univ., Baton Rouge, Louisiana. 181 pp. Helm, S.R. 1995. Assessment of swamp rabbit habitat in Louisiana forested wetlands impacted by Hurricane Andrew. M.S. Thesis, Louisiana State Univ., Baton Rouge, Louisiana. 75 pp. Helm, S.R. and R.H. Chabreck. 2004. Response of understory plant cover to Hurricane Andrew damage in the Atchafalya Basin, Louisiana. Proc. Louisiana Acad. Sci. 65:17-21. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States The flora of the United States comprises about 16,000 species. The United States possess one of the most diverse temperate floras in the world, comparable only to that of China. Moreover, subtropical and tropical flora covers Hawaii and the southernmost part of Florida. , Canada, and Greenland. Second ed. Timber Press, Portland, OR. Vol. 1. 622 pp and Vol. 2. 816 pp. Lowery, G.H. Jr. 1974. The mammals of Louisiana CODE, OF LOUISIANA. In 1822, Peter Derbigny, Edward Livingston, and Moreau Lislet, were selected by the legislature to revise and amend the civil code, and to add to it such laws still in force as were not included therein. and its adjacent waters. Louisiana State Univ. Press, Baton Rouge, Louisiana. 565 pp. Richardson, L.V. 1963. Food preferences and nutritive nutritive /nu·tri·tive/ (noo´tri-tiv) nutritional. nu·tri·tive adj. 1. Of or relating to nutrition. 2. Nutritious; nourishing. content of selected plants fed to cottontail and swamp rabbits. M.S. Thesis, Louisiana State Univ., Baton Rouge, Louisiana. 77 pp. Salyer, M.R. 1995. Assessment of Hurricane Andrew damage to white-tailed deer white-tailed deer or Virginia deer Common reddish brown deer (Odocoileus virginianus), an important game animal found alone or in small groups from southern Canada to South America. habitat in forested wetlands in Louisiana. M.S. Thesis, Louisiana State Univ., Baton Rouge, Louisiana. 58 pp. Sims, J. 1956. Rabbit investigations. Page 108 In Sixth biennial report of Louisiana Wild Life and Fish. Comm. 185 pp. Smith, C.C. 1940. Notes on the food and parasites of the rabbits of a lowland area in Oklahoma. J. Wildl. Manage. 4(4):429-431. Sullivan, A.D. 1966. Food preferences of swamp rabbits for selected plants. M.S. Thesis, Louisiana State Univ., Baton Rouge, Louisiana. 53 pp. Terrel, T.L. 1972. The swamp rabbit (Sylvilagus aquaticus) in Indiana. Amer. Midl. Natur. 87(2):283-295. Toll, J.E., T.S. Baskett, and C.H. Conaway. 1960. Home range, reproduction, and foods of the swamp rabbit in Missouri. Amer. Midl. Natur. 63(2):398-41. U.S.D.I. Geol. Surv. 1953a (photorev. 1980). Addis, Louisiana quadrangle quadrangle Rectangular open space completely or partially enclosed by buildings of an academic or civic character. The grounds of a quadrangle are often grassy or landscaped. . 7.5 min. series. U.S.D.I. Geol. Surv. 1953b (photorev. 1980). Grosse Tete SW, Louisiana quadrangle. 7.5 min. series. Steven R. Helm (1) and Robert H. Chabreck School of Renewable Natural Resources, Louisiana State University, Baton Rouge, LA 70803 Steven Helm corresponding author. Current address: U.S. Army Corps of Engineers, P.O. Box 2946 (CENWP-PME), Portland, OR 97208-2946
Table 1. Plant abundance (frequency per [m.sup.2]) and number of
cuttings by swamp rabbits, Atchafalaya Basin, Louisiana, summer 1994.
Number
Taxon (1) Habit Frequency Cuttings
Dewberry (Rubus spp.) Woody 43.1 24
Savannah panicgrass (Phanopyrum Herbaceous 5.6 20
gymnocarpon)
Greenbrier (Smilax spp.) Woody 4.4 14
False nettle (Boehmeria cylindrica) Herbaceous 43.6 8
Smartweed (Polygonum spp.) Herbaceous 17.1 5
Sugarberry (Celtis laevigata) Woody 18.4 5
Green ash (Fraxinus pennsylvanica) Woody 13.0 4
Thistle (Cirsium spp.) Herbaceous 4.2 3
Thoroughwort (Eupatorium Herbaceous 8.9 3
semiserratum)
Waterwillow (Justicia ovata) Herbaceous 19.3 3
Japanese honeysuckle (Lonicera Herbaceous 6.5 2
japonica)
Sedge (Cyperaceae) Herbaceous 21.0 2
Peppervine (Ampelopsis arborea) Herbaceous 27.5 2
Heart-leaf peppervine (Ampelopsis Herbaceous 0.5 1
cordata)
Deciduous holly (Ilex decidua) Woody 1.3 1
Trumpet creeper (Campsis radicans) Herbaceous 1.6 1
Seedbox (Ludwigia spp.) Herbaceous 1.7 1
Swamp privit (Forestiera acuminata) Woody 1.8 1
Elephant's-foot (Elephantopus Herbaceous 2.6 1
tomentosus)
Creeping cucumber (Melothria Herbaceous 3.9 1
pendula)
Swamp dogwood (Cornus drummondii) Woody 6.0 1
Elm (Ulmaceae) Woody 8.1 1
Virginia knotweed (Polygonum Herbaceous 11.7 1
virginianum)
Poison ivy (Toxicodendron radicans) Woody 49.2 1
Unknown NA NA 11
(1) Scientific names in accord with Kartesz (1994).
Table 2. Plant abundance (frequency per [m.sup.2]) and number of
cuttings by swamp rabbits, Atchafalaya Basin, Louisiana, winter 1995.
Taxon (1) Habit Frequency Number Cuttings
Dewberry (Rubus spp.) Woody 44.8 28
Greenbrier (Smilax spp.) Woody 5.6 27
Woody stems (unidentified) Woody 49.1 25
Savannah panicgrass (Phanopyrum Herbaceous 4.1 4
gymnocarpon)
Butterweed (Senecio glabellus) Herbaceous 35.8 3
Willow oak (Quercus phellos) Woody 0.8 2
Japanese honeysuckle (Lonicera Herbaceous 4.2 2
japonica)
Violet (Viola spp.) Herbaceous 21.1 2
Red-berried moonseed (Cocculus Herbaceous 1.3 1
carolinus)
Thistle (Cirsium spp.) Herbaceous 5.0 1
Water willow (Justicia ovata) Herbaceous 6.6 1
(1) Scientific names in accord with Kartesz (1994).
|
|
||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion